Writing Apache Modules with Perl and C: The Apache API and mod_perl

Apache is the most popular web server on the Internet because it is free, reliable, and extensible. The availability of the source code and the modular design of Apache makes it possible to extend web server functionality through the Apache API.For the most part, however, the Apache API has only been available to C programmers, and requires rebuilding the Apache server from source. mod_perl, the popular Apache module used primarily for enhanced CGI performance, changed all that by making the Apache API available to Perl programmers. With mod_perl, it becomes simple to develop Apache modules with Perl and install them without having to rebuild the web server.Writing Apache Modules with Perl and C shows how to extend web server capabilities regardless of whether the programming language is Perl or C. The book explains the design of Apache, mod_perl, and the Apache API. It then demonstrates how to use them to perform for tasks like the following:

• Rewriting CGI scripts as Apache modules to vastly improve performance
• Server-side filtering of HTML documents, to embed special markup or code (much like SSI)
• Enhancing server log functionality
• Converting file formats on the fly
• Implementing dynamic navigation bars
• Incorporating database access into CGI scripts
• Customizing access control and authorization to block robots or to use an external database for passwords

The authors are Lincoln Stein and Doug MacEachern. Lincoln is the successful author of How to Set Up and Maintain a World Wide web Site and the developer of the widely used Perl CGI.pm module. Doug is a consultant and the creator of the innovative mod_perl Apache module.

"Writing Apache Modules with Perl and C shows how to extend the capabilities of the Apache web server. It explains the design of Apache, mod_perl, and the Apache API, then demonstrates how to use them for: Rewriting CGI scripts as Apache modules to vastly improve performanceServer-side filtering of HTML documents to embed special markup or code (much like SSI)Enhancing server log functionalityConverting file formats on the flyImplementing dynamic navigation barsIncorporating database access into CGI scriptsCustomizing access control and authorization to block robots or to use an external database for passwords Lincoln Stein is the successful author of "How to Set Up and Maintain a World Wide web Site and the developer of the widely used Perl CGI.pm module. Doug MacEachern is a consultant and the creator of the innovative mod_perl Apache module.

This guide to Web programming teaches readers how to extend the capabilities of the Apache Web server. The book explains the design of Apache, mod_perl, and the Apache API, then demonstrates how to use them to rewrite CGI scripts, filter HTML documents on the server-side, enhance server log functionality, convert file formats on the fly, and more.

Doug MacEachern has been addicted to Perl and web servers since early 1994 when he was introduced to Plexus as a student employee at the University of Arizona. Soon after returning to his home town of Boston, Massachusetts, and entering the "real world," he discovered the Apache web server, and since early 1996, he has been gluing Perl into all its nooks and crannies. His day job has consisted of integrating various other technologies with the Web, including DCE, Kerberos, and GSSAPI, but Perl has been the only one he cannot let go of. Doug has continued as a developer disguised as a consultant since the start of 1998, spending most of his time between Auckland, New Zealand, and San Francisco, California, with time at home in Boston during the warmer months. Doug likes to spend his time away from software--far, far away, sailing on the ocean, diving below it, or simply looking at it from a warm, sandy beach where technology doesn't go much beyond thatched huts and blenders.

Lincoln Stein is an assistant investigator at Cold Spring Harbor Laboratory, where he develops databases and user interfaces for the Human Genome Project using the Apache server and its module API. He is the author of several books about programming for the Web, including The Official Guide to CGI.pm, How to Set Up and Maintain a Web Site, and Web Security: A Step-by-Step Reference Guide.

Preface; What You Need to Know to Get the Most out of This Book; How This Book Is Organized; Conventions; The Companion Web Site to This Book; Using FTP and CPAN; Comments and Questions; Acknowledgments; Chapter 1: Server-Side Programming with Apache; 1.1 Web Programming Then and Now; 1.2 The Apache Project; 1.3 The Apache C and Perl APIs; 1.4 Ideas and Success Stories; Chapter 2: A First Module; 2.1 Preliminaries; 2.2 Directory Layout Structure; 2.3 Installing mod_perl; 2.4 "Hello World" with the Perl API; 2.5 "Hello World" with the C API; 2.6 Instant Modules with Apache::Registry; 2.7 Troubleshooting Modules; Chapter 3: The Apache Module Architecture and API; 3.1 How Apache Works; 3.2 The Apache Life Cycle; 3.3 The Handler API; 3.4 Perl API Classes and Data Structures; Chapter 4: Content Handlers; 4.1 Content Handlers as File Processors; 4.2 Virtual Documents; 4.3 Redirection; 4.4 Processing Input; 4.5 Apache::Registry; 4.6 Handling Errors; 4.7 Chaining Content Handlers; 4.8 Method Handlers; Chapter 5: Maintaining State; 5.1 Choosing the Right Technique; 5.2 Maintaining State in Hidden Fields; 5.3 Maintaining State with Cookies; 5.4 Protecting Client-Side Information; 5.5 Storing State at the Server Side; 5.6 Storing State Information in SQL Databases; 5.7 Other Server-Side Techniques; Chapter 6: Authentication and Authorization; 6.1 Access Control, Authentication, and Authorization; 6.2 Access Control with mod_perl; 6.3 Authentication Handlers; 6.4 Authorization Handlers; 6.5 Cookie-Based Access Control; 6.6 Authentication with the Secure Sockets Layer; Chapter 7: Other Request Phases; 7.1 The Child Initialization and Exit Phases; 7.2 The Post Read Request Phase; 7.3 The URI Translation Phase; 7.4 The Header Parser Phase; 7.5 Customizing the Type Checking Phase; 7.6 Customizing the Fixup Phase; 7.7 The Logging Phase; 7.8 Registered Cleanups; 7.9 Handling Proxy Requests; 7.10 Perl Server-Side Includes; 7.11 Subclassing the Apache Class; Chapter 8: Customizing the Apache Configuration Process; 8.1 Simple Configuration with the PerlSetVar Directive; 8.2 The Apache Configuration Directive API; 8.3 Configuring Apache with Perl; 8.4 Documenting Configuration Files; Chapter 9: Perl API Reference Guide; 9.1 The Apache Request Object; 9.2 Other Core Perl API Classes; 9.3 Configuration Classes; 9.4 The Apache::File Class; 9.5 Special Global Variables, Subroutines, and Literals; Chapter 10: C API Reference Guide, Part I; 10.1 Which Header Files to Use?; 10.2 Major Data Structures; 10.3 Memory Management and Resource Pools; 10.4 The Array API; 10.5 The Table API; 10.6 Processing Requests; 10.7 Server Core Routines; Chapter 11: C API Reference Guide, Part II; 11.1 Implementing Configuration Directives in C; 11.2 Customizing the Configuration Process; 11.3 String and URI Manipulation; 11.4 File and Directory Management; 11.5 Time and Date Functions; 11.6 Message Digest Algorithm Functions; 11.7 User and Group ID Information Routines; 11.8 Data Mutex Locking; 11.9 Launching Subprocesses; Standard Noncore Modules; The Apache::Registry Class; The Apache::PerlRun Class; The Apache::RegistryLoader Class; The Apache::Resource Class; The Apache::PerlSections Class; The Apache::ReadConfig Class; The Apache::StatINC Class; The Apache::Include Class; The Apache::Status Class; Building and Installing mod_perl; Standard Installation; Other Configuration Methods; Building Multifule C API Modules; Statistically Linked Modules That Need External Libraries; Dynamically Linked Modules That Need External Libraries; Building Modules from Several Source Files; Apache:: Modules Available on CPAN; Content Handling; URI Translation; Perl and HTML Mixing; Authentication and Authorization; Fixup; Logging; Profiling; Persistent Database Connections; Miscellaneous; Third-Party C Modules; Content Handling; International Language; Security; Access Control; Authentication and Authorization; Logging; Distributed Authoring; Miscellaneous; HTML::Embperl--Embedding Perl Code in HTML; Dynamic Tables; Handling Forms; Storing Persistent Data; Modularization of Embperl Pages; Debugging; Querying a Database; Security; An Extended Example; Colophon;